Answer:
a.Attractive

Explanation:
When it comes to charges, the charges which are alike repel each other and the charges which are different will attract each other.
Here, there is a proton and electron which are different particles hence, they will attract each other.
= Charge of electron and proton = 
r = Distance between them = 997 nm
k = Coulomb constant = 
Force is given by

The force of attraction between the particles will be 
Answer:
#see solution for details
Explanation:
-Uncertainty refers to an estimate of the amount by which a result may differ from this value,
-Precision refers to how closely repeated measurements agree with each other.
-Accuracy refers to how closely a measured value agrees with the correct value.
-The number of significant figures is the number of digits believed to be correct by the person doing the measuring. Therefore, choosing the correct number of significant figures reduces the deviation from the point of accuracy/uncertainty or precision and thereby reducing margin of error in the ensuing calculations.
Answer:
D. It has been demonstrated to be without exception under certain stated conditions.
Explanation:
A principle is simply a proposition based on some results from some experiments. A principle becomes a law when it gains strength. That is when other scientists support and back it.
A scientific law is a statement that describes a natural phenomenon and is not contradicted by repeated experiments over the time.
Sir Isaac Newton's law of gravitation stated "A gravitational force exists between all objects in the universe. This force is directly proportional to the masses of the two objects and inversely proportional to the distance between them."
His law explained that every body in the universe attracts every other body. It explained that it is not just Earth that pulls us towards it. But even sun and moon has their own gravitational pull and so does all other objects. It is just that the Gravitational pull of some objects is negligible.
Newton's law of Gravitation is considered a universal law because it is applicable to almost all the bodies in the universe and is demonstrated to be correct for them under certain conditions.
Answer:
the magnitude and direction of d → B on the x ‑axis at x = 2.50 m is -6.4 × 10⁻¹¹T(Along z direction)
the magnitude and direction of d → B on the z ‑axis at z = 5.00 m is 1.6 × 10⁻¹¹T(Along x direction)
Explanation:
Use Biot, Savart, the magnetic field

Given that,
i = 1.00A
d → l = 4.00 m m ^ j
r = 2.5m
Displacement vector is


=2.5m
on the axis of x at x = 2.5

r = 2.5m
And unit vector


Therefore, the magnetic field is as follow


(Along z direction)
B)r = 5.00m
Displacement vector is


=5.00m
on the axis of x at x = 5.0

r = 5.00m
And unit vector


Therefore, the magnetic field is as follow


(Along x direction)
What's the weight of the pear ?
Weight = (mass) x (gravity) = (1 kg) x (9.8 m/s²) = 9.8 Newtons.
OK. We know there's a force of 9.8 Newtons acting downwards on the pear.
Is the pear accelerating ? No ! It's just laying there on the table.
If it's not accelerating, then we know that the net force on it must be zero.
So there must be ANOTHER force acting UPWARDS on it, to exactly
cancel out the downward force of its weight. THAT's the "normal" force ...
the upward force that the table exerts on the pear. It must also be 9.8N,
but UPwards, so that if you add it to the weight, the sum is zero.